In conventional cane harvesters stalks of cane are "topped" to remove the leafy top of the cane, cut at their base, and fed butt first by feed rollers into cutter means which severs the cane into billets. The cutter means conventionally comprise a pair of counter rotating blades which are so controlled that they periodically come together to sever the stalks of cane into billets of a predetermined length. The billets then fall from the cutting means into a bin from whence they are transported by conventional conveyor means to a discharge point of the harvester. The sugar cane stalks fed to the harvester are accompanied by considerable quantities of trash comprising leaves of the cane plant and other unwanted vegetable matter. This trash is conventionally separated from the cane after it has been severed into billets by the use of extractor fans which produce a suction draught drawing the trash upwardly away from the cane billets and by the use of slatted floor conveyors which allow dirt and other small portions of trash to drop through the conveyor.
Australian patent specification 257,323 discloses a cane harvester with chopping means comprising a blade mounted to rotate in a plane and to move downwardly past a feed path for sugar cane stalks and to co-operate with a fixed blade below the feed path to sever the sugar cane into billets. Throwing plates are provided to project perpendicularly to the blade to engage the cut billets and, after moving them around a circular chute, to throw them upwardly. This arrangement suffers from a first disadvantage in that the direction of travel of the cut billets must be changed through 180.degree. thereby using unnecessary energy. The use of a blade moving in a plane has further the disadvantage that the cutting velocity of the blade is increased as one moves radially outwardly along the blade This results in an uneven departure velocity for the cut billets. In the arrangement according to specification 257,323 the cut billets must be thrown radially outwardly until they hit the semicircular chute before being contacted by the throwing plate. This contact with the chute can give rise to physical damage to the billets which reduces their sugar content particularly at the relatively high speeds of the movable blade.